Drought puts historic Melbourne trees at risk

AM - Friday, 12 January , 2007 08:18:00

Reporter: Alison Caldwell

PETER CAVE: There are concerns that Victoria's reputation as a garden state could be at risk, with the drought slowly killing many of Melbourne's stately trees.

Dozens of historic elm trees, which have lined the Yarra River and the sweeping boulevards of Melbourne for over 100 years, are either dead or dying after falling victim to the drought.

Alison Caldwell filed this report.

(sound of crunching leaves underfoot)

ALISON CALDWELL: This is definitely not the sound of summer. I'm walking on a crackling bed of brown and yellow leaves, which have been shed from their trees in Melbourne's Royal Botanic Gardens.

The city has endured a string of days over 30 degrees, but for some reason the trees think it's autumn.

Dr Greg Moore is a tree ecologist at the University of Melbourne.

GREG MOORE: It just shows you how trees respond to drought. What's happened of course is many of the deciduous trees are going into an early autumn, and they're doing a trade off. They can keep their leaves and run the risk of being stressed through drought, or they can shorten their growing season, drop their leaves, cut their losses and then hope they get a good spring.

And it's most obvious in the exotic deciduous trees, but many of our native trees are doing exactly the same thing, the Spotted Gum, the River Red Gum, they're also dropping leaves and flowers and fruits and again, that will save them water.

ALISON CALDWELL: Is there a possibility that some of these beautiful trees that we see in Melbourne's gardens, the parks, which have shed their leaves, that they might die?

GREG MOORE: Not all of the trees are going to survive this summer. Not all survived last summer or the summer before. And it's not just the exotic trees that are at risk. A number of our River Red Gums, that sort of nobody notices and nobody has to care for, have died over the last three or four years, and some of those, have been really old trees, well predating the European arrival in Victoria.

So we have lost trees and we will lose trees. It's inevitable. Hopefully, not too many.

ALISON CALDWELL: The worst-recorded drought ever is forcing the Melbourne City Council to make some tough decisions about which trees to save.

It's prioritising trees in the city's heritage listed gardens and those along Melbourne's main boulevards.

Dr Greg Moore recommends using drip systems and lining the base of trees with a healthy layer of mulch.

In the long run he's optimistic.

GREG MOORE: We're going to use water much more sensibly and much more efficiently. We're going to develop our native vegetation much more than we have in the past, and we're going to know which trees are really good at coping with drought and which ones are not.

And I'm quite confident that when you come to our cities and parks in 100 years' time, they'll still be spectacular places.